Tube sheet and smoke box for horizontal flue boiler having return fire tubes



July 22, 1952 1 J. HENC 2,504,081

TUBE SHEET AND SMOKE BOX FOR HORIZONTAL ELUE EoIEER HAVING RETURN EIEE TUBES.

A T TORA/YS' July 22, 1952 L. J; HENc 2,604Q081` TUBE SHEET ANDV SMOKE BOX FOR HORIZONTAL Y FLUE BOILER HAVING RETURN FIRE lTUBES Filed July 5, 1950 2 Sl-IEETS-SHEET v2 a m a 'sa Q l l@ m wi..

NI @3% 43% Q 'n AT T ONE'YS' Patented July 22, 1952 TUBE SHEET' AND SMOKE B0X For; Honi- Z'OTAL FLUE BOILER FIRE TUBES yHAVING .RETURN Louis' Jahn Hem, roumaines., assigiir to Struthers-Wclls' Corporation, Titusville, Pa., a corporation of Maryland y v"iipplitation July 5, 195o, seainizalis 1 claim. (o1. iszi495 v 1 l This invention relates to a boiler construction for steam generatorsvan'd the like and is more particularly shownas embodied in a horizontal v sie tube type or boiler. y y

This application is a companion to my copndlng application, Serial No.y l'79,93l, y filed August 1'7, 1950, now Patent No. 2,595,523, for Removable Smoke Box Closure. a V H vOn' of the principal objects of the invention is to provide a boiler construction in which a cover provides a gas transition chamber from tli main combustion tube to a surrounding series of cour'iterfiovf boiler tubes and in which the cover will last longer than similar covers heretofore' used, such greater life beingachieved in part by water cooling the nm of ldie cover.; a

Another object is to provide a boiler constructionv in'whi'ch a Yrefractory lined cover provides such a transition chamber from the main combus'tionv tube to a surrounding series of counter.- fio'w boiler tubes and in which a stronger vand tighter joint is obtainedby using higher joint pressurein' applying the` cover, such stronger and tighter joint being'a function both of water c'oolin'gtle rim ofl the cover at the joint and also through iitting the rim of the cover around a projecting 'annular subhead connecting one end of the main combustiontub'e with the adjacent main ytransverse end head or tubev sheet and forming a water cooled annular protuberanc'e or extension of the main combustion tube.

'Anoth-: object is to providel a joint between such a refractory lined cover and projecting' ann lar subhead which is of labyrinth form -in cross section thereby to inhibit the leakage of'gas past the joint; 'The joint shown has three right angle turns which not only acty to prevent leakage but also greatly reduce the. velocity oi any gas' which does escape past the joint thereby to' eliminate the harmful high temperature blow'-torclrv effect of gases escaping atfhigh velocity*l Another object is to increase thel efficiency of operation of a boiler having such a gas'transivtion chamber and to reduce the possibility of structural failures. y a n u a Y Other objects 'and advantages-"of the invention will be apparent fromv the following description and drawings in which: l Y Figure l isv a vertical llongitudinal section through ahorizontal rire tube type of boiler embodying the' present invention. v l

Fig-urev 2: is an enlarged fragmentary ysectional view` taken generally online 2 72, Figurerl.'

Figure 3 1s a fragmentary vertical longitudinal 2 p A Figure 4 isa fragmentary horizontal section taken on lined-LFigure 2.

The invention is shown as embodied in a horilzontal ire tubetype of boiler having a cylindrical boiler shell lprovided with a steam outlet il and havingannular rows of external angles or lugs I2 ancl'l3 welded to its front and rear ends, respectively, l

The front endo'f the boiler shell i0 is closed by a circular front vcover or cap I4 which is shown as secured to the front row of angles i2 of the boiler shell by yas'e'ries of Vstud bolts l5, a suitable sealing gasket 'It being interposed between the front cover or cap and the front end of the boiler shell. The front cover or cap M is shown as lined with two layers IB of insulating,r material and is provided with an outwardly necked opening 1 9 throughy which the 'burner equipment, indicated generally Vat 20, projects.

The rear end of the boiler Shen se is closes by a. circular rearvcover or cap 2| whichv is shown as secured tothe rear row of angles i3 of the boiler shell' by a series of stud bolts 22, a suitable sealing gasket'23 being interposed betweenthe `rear cover or capxand the rear end of the boiler shell. The rear cover or cap' 2l isshown as lined with two' layers 24 of insulating material. n

As best shown in Fig. i, a front main transverse end head or tube sheet 25 is welded'in the frontend of theboiler shell, this main transverse end 'head being shown as having' a forwardly projecting peripheral flange 2tY welded to tli'ejinside ofthe boiler shell Il) in spaced relationto the front cover or cap I4 so as to provide a gas return chamber 2B at the forward end of the boiler. This, gas return chamber is shown as provided with a gas relief vent 29. Coaxially with theopening lil in thefront cover or cap lll, the irontr'nain transverse end head or tube sheet 25 is provided Witha rearwardly necked opening 30, the flange` of which is'indicated at 3l. To the end ofl this flange 3| is welded, as at 32, the for- .'ward end ofthe tubular internal furnace shell or 4coir1b1'1stion tube 33." This combustion tube 33 can be of plaincylindrical form but is illustrated as having conventional corrugations. A sleeve 3Q is shown as arranged concentric with the openings "IQ and '31)r` and interposed between the front cap or cover Hl` and the front main transverse end head orr tube sheet 25 to house the burner equipment 2l).v y n A rear main transverse end head or tube sheet 35vis welded to the rear end o the boiler shell, this main transverse end headv beingshown as havinga' rearwardly projecting peripheral iiange 33 welded to the inside of the boiler shell I0 in spaced relation to the rear cover or cap 2| so as to provide a last gas or gas outlet chamber 31 at the rear end of the boiler. This gas outlet chamber is provided with a gas discharge outlet flue 38. The rear main transverse end head or tube sheet 35 is provided with a circular opening 39 which is concentric with the internal furnace shell or combustion tube 33 but is of considerably larger diameter than this combustion tube.

The burner equipment 20 can be of any conventional form and is shown in Fig. 1 as comprising a block 40 of refractory material fitted within the sleeves 34 and frontend of the com` bustion tube 33 and having a coaxial conical bore 4| converging toward and opening into the combustion tube 33 and forming a primary combus tion chamber. This bore or combustion chamber 4| is shown as extended forwardly by a metal sleeve 42 interposed between the block 40 and the front cap or cover I4 of the boiler. A second block 43 of refractory vmaterial projects through the forwardly necked opening I9 of the front cap or cover I4 of the boiler into the metal sleeve 42. This second block 43 is provided with a bore 44 for reception of the usual fuel nozzle (not shown). The refractory block 43 can be supported by any conventional supporting structure, indicated generally at 45, and preferably in such manner as` to leave an annular air inlet space 46 to the combustion chamber 4|.

The invention is primarily directed t the projecting subhead indicated generally at 50 and `which is disposed, as best shown in Figs. 1 and 4,

in the opening 39 through the rear tubesheet or transverse end head 35 and which connects this tube sheet with the adjacent end of the tubular internal furnace shell or combustiontube 33.

This projecting subhead is in the form of an annular shell which is U-shaped in cross section, having a vertical annular rear wall an outer flange 52 which projects axially forwardly through the opening 39 in the rear tube sheet or transverse end head 35, and an inner annular flange 53 which projects axially forwardly into engagement with the rear edge of the internal furnace shell or combustion tube 33. The abutting edgesof the combustion tube 33 and inner flange 53 ofthe subhead are butt welded, and the edge of theopening 39 in the rear tube sheet 35 can be welded to the outer flange 52 of the subhead. The subhead 50 thereby is in the form of a rearwardly extending annular protuberance from the combustion tube and rear tube sheet of the boiler.

Inner or forward pass @boiler tubes 55, as best shown in Fig. 1, connect the projecting subhead. 50 Vwith the front main transverse end head or tube sheet 25. These boiler tubes are arranged inan annular row raround the combustion tube 4 wardly through outer or rearward pass boiler tubes 58 which, as best shown in Figs. 1, 2 and 4, connect the main transverse end heads or tube sheets 25 and 35 and discharge the products of combustion into the gas outlet chamber 31. v

It will be seen from Fig. 1 thatthe body of water 56 contacts and hence water coolsV the boiler shell l0 main transverse end heads or tube e sheets 25 and 35; main combustion tube 33; the

33 and are immersed in the body 56 of water surrounding this combustion tube. TheV rear ends of these boiler tubes 55 extend through and are secured to the vertical annular rear wall 5I of the projecting subhead 5B and the front ends of these Iboiler tubes extend through and are secured Y to the front tube sheet 25. Accordingly the products of co-mbustion leaving the rear end of the tubular internal furnace shell yor combustion tube 33 travel radially outwardly around the projecting subhead 50 and enter the inner or forward pass boiler tubes 55 and are conducted to the chamber 28 between the front cover or cap 4 and front tube sheet 25. From this chamber 28 the products of combustion are conducted reartwo series of boiler tubes 55 and 58; and also the projecting subhead 50. It will particularly be notedthat the latter is water cooled.

A feature of the invention resides in the construction of a cap or cover, indicated generally at 6U, which is fitted to the projecting subhead 50 andwhich, as best shown in Figs. l and 2, forms a gas transition chamber 6| between the rear end of the combustion tube 33 and the rear ends of the inner or forward pass tubes 55. This cap or cover comprisesa circular metal plate 62 having a forwardly projecting metal rim 63 which engages the rear face of the rear main transverse end head or tube sheet 35 in outwardly spaced relation to the projecting subhead 5D. This rim can be secured to this rear tube sheet 35 by stud bolts 64, best shown in Figs.V 2 and 3,v projecting rearwardly from this tube sheet through loops 65 provided by welding VU-shaped straps to the exterior of the cover rim 63. Nuts 6G on the ends of the stud bolts 64 are tightened against these loops 65 to draw the cap or cover 60 tightly against the rear tube sheet 35. For convenience in removal the cap or cover 50 can be supported by a davit 61 of any suitable construction.

The cap or cover 59, as shown in Figs. 1, 3 and 4, is linedwith refractory material 'I0 which is hollowed out at its center to provide the gas transition chamber 6|. This refractory material 10 is formed. to pro-vide a forwardlyv projecting rim 1| which lines the metal rim 63 and which is shaped to conform generally tothe outer flange 53 of the projecting subhead 5I) as well as to the rear face of the rear tube sheet 35 and the rear face of the vertical metal `rear wallv 5| of the subhead. To insure a tight seal at this joint of the cover or cap 60, a ring 12 of sealing material is provided, this ring being interposed between the rim 1| ofthe refractory liningJll and the rear main transverse end head or tube sheet 35; between this rim 1| and the outer flange 53 of the projecting subhead 50; and .between this rim 1| and the outer part of the vertical rear wall5| of this subhead 5I);v

To retain the refractory. lining 1.0 in the sheet metal shell of the cover, the conventional short lengths 13 of `Vr-shaped wire ares'howninvFigs. 1 and 3 as welded at their apices to the metal shell and as embedded in the refractory.

In the operation of the boilerfthe products of combustion generated in thecombustion chamber 4| travel longitudinally along the main combustion tube33 toward the right hand end thereof as viewed in Figure 41.V On leaving this combustion tube 33 the gases enterthe gas transition chamber 6|y and travel radiallyloutwardly into the annular series of inner boiler `tubes 55 where thesegases travel countercurrent to the flow of gas in the main combustion tube 33, that is to the left as viewed in Figure 1. At the front end of the boiler the gases leaving the innerfboiler tubes 55 enter the chamber 28 between the front cover or cap |4 and the .front main transverse end head or tube sheet 25. From this chamber 28 the gases enter the outer series of boiler tubes 58 which connect the .front tube Ysheet 25 with cape of gas.

the rear tube sheet 35 land are discharged into the gas outlet chamber 31 at the rear of the boiler and escape through the stack or gas discharge 38.

The gas transition chamber 6l `is provided by the cap or cover 6U and the present invention is essentially concerned with providing a labyrinthian and Water cooled joint at the rim of this cap or cover 60 so as to prevent the escape of hot products of combustion from the gas transition chamber 6| directly to the gas outlet chamber 31. To this end the projecting subhead u is provided which connects the rear end of the main combustion tube 33 with the rim provided by the larger opening 39 in the rear main transverse end head or tube sheet 35. It will particularly be noted that the axially extending anges 53 and l 52 of this projecting subhead 50 are connected to the main combustion tube 33 and rear tube sheet 35 in such manner that this subhead 50 protrudes rearwardly beyond the main combustion tube and rear tube sheet, that is, toward the rear end of the boiler shell I0. The rim 1l of the refractory line of the cap or cover 60 is formedto fit the rear face of the rear main transverse end head or tube sheet 35; the outer flange 52 of the projecting subhead 50, and the vertical rear wall 5l of this projecting subhead. Accordingly, it will be seen that in order to escape from the gas transition chamber 6| to the gas outlet chamber 31, it is necessary for the gases to make three right angle turns. Such escape is, of course, prevented by the ring 12 of sealing material, but, in the event this seal gives Way, it will be seen that the requirement that the escaping gases make three right angle turns would materially slow down the velocity of such leaking gas and prevents blow torch action of this escaping gas.

Even more important is the fact that not only is the gas, so escaping. cooled by the water containing projecting subhead 50 but also that the entire refractory rim 1| of the cover or cap 60 is also water cooled by the projecting subhead 50. This water cooling of the refractory rim 1| of the cover or cap 60 insures that the joint of this cap or cover Will last much longer than if it were left uncooled. Further, a much higher joint pressure can be employed where this joint is so cooled, this being effected by drawing up the nuts 66 to a greater degree. With such higher joint pressure, a tighter joint is obtained for the cover v or cap 60 sovas to further insure against the es- Also, as previously indicated, any gas which does escape is water cooled by the projecting subhead 50 so that in addition to having a low velocity these gases also have a lower temperature thereby to reduce their destructive eiect.

From the foregoing, it will be seen that the present invention provides a boiler construction in which the joint between the cap or cover forming a gas transition chamber and the adja-' cent metal parts of the furnace is adequately water cooled and also of labyrinthian form so as to stand up under conditions of severe and constant use without danger of rapid deterioration. It will also be seen that if leakage of gas does occur from the transition chamber the destructive effect of such leakage is very materially reduced by the practice of the present invention.

I claim:

In a boiler, a boiler shell, a main transverse end head across one end of said shell in spaced relation to said one end of said shell, a combustion tube within said shell and having one end arranged adjacent an opening in said main trans verse end head and projecting toward said one end of said shell, said opening being of larger size than said combustion tube, an `annular subhead of U-shaped form in cross section at each side and having an inner annular ange projecting away from said one end of said shell toward said one end of said combustion tube and joined thereto and having an outer annular flange projecting axially away from said one end of said shell toward said main transverse end head and joined to said main transverse end head around said opening whereby said subhead provides an annular protuberance projecting from said main transverse end head toward said one end of said shell, boiler tubes extending through and secured to said subhead to conduct the gases from said combustion tube in counterlow relation to the gases passing through said combustion tube, a cover forming a gas transition chamber between said corresponding end of said combustion tube and said boiler tubes and comprising a metal cover shell having a rim projecting axially into engagement with the outer face of said main transverse end head and embracing said subhead in spaced relation thereto, a lining of refractory material in said metal cover shell, said lining, including a rim portion generally conforming to said outer flange of said subhead and the adj acentpart of said end head and a ring of sealing material interposed contiguously between said rim portion of said lining and at least one of the surfaces provided by said end head and said subhead, and means securing said rim toA said main transverse end head. Y

' y LOUIS JOI-17N HENC.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,950,756 Sharp Mar. 13, 1934 2,126,417 Sharp Aug. 9, 1'938 2,264,226 Toner Nov. 25, 1941 2,464,701 Lyke Mar. 15, 1949 

